The main character in the tale is Nodoka Hanadera, a frail yet positive young student who has relocated to Sukoyaka City, renowned for its healthy atmosphere. Nodoka forms fast friendships with two classmates: Chiyu Sawaizumi, a kind-hearted athlete with a family-owned hot spring inn, and Hinata Hiramitsu, a trendy young girl whose father is a veterinarian. Shortly after arriving in the city, Nodoka comes across a sickly puppy in the forest. Three magical creatures, Rabbirin, Penguitan, and Nyatoran, inform her that the pup, Princess Latte, can only recover by conquering a malevolent monster, the "Mega Byogen," and purifying the polluted land it has overrun. Despite having no unique abilities, Nodoka bravely prepares to take on the challenge and watches as Princess Latte suffers terribly. Impressed with Nodoka's courage, Rabbirin offers her a deal, transforming her into the superhero known as "Cure Grace." With her newfound strength, Nodoka defeats the Byogen and heals Princess Latte. Unluckily, the Byogen and their superiors remain on the offensive, prompting Penguitan and Nyatoran to join Chiyu and Hinata, respectively. They become known as "Cure Fontaine" and "Cure Sparkle," giving them extraordinary powers. Now, it is up to the three Precure heroes, along with their animal companions, to stop the Byogen's progress and safeguard the planet from their contagions!